---
id: "bug-1736"
status: "partial"
status_updated: "2026-09-24"
status_note: "swap/tasks/peak_cpu_time fixed 5c2c6664; peak_cpu_duration/efficiency still not computed"
component: "controller"
severity: "unknown"
timestamp: "2026-08-30T10:45:00Z"
last_seen: "2026-09-19T09:00:00Z"
occurrences: 1
files: ["src/worker/src/xcecd_cgroups.c (collect_job_rusages -- already sends memory_swap/tasks_current", "no controller-side field to receive them)", "src/include/xce/types.h (xce_host_runusage_t -- would need new fields for swap/task-count; xce_job_runusage_t -- the peak/efficiency fields with no producer)", "src/controller/misc.c (update_host_runusage -- would need new parse branches)", "src/controller/job.c (update_job_rusages -- same open FIXME as bug-1735", "this is the other half of what it would need to cover)"]
tags: ["worker", "controller", "resource-usage", "rusage", "display-only", "reporting-only", "priority-low", "split-2026-08-30", "no-scheduling-impact", "static-analysis-only", "unreproduced-in-sandbox", "needs-design-not-just-fix", "peak-cpu-time-fixed", "swap-taskcount-fixed", "efficiency-fields-remain-scope-decision"]
related: ["bug-1735"]
fix_commits: ["5c2c6664"]
legacy: true
---

# bug-1736: display/reporting only, not consumed by any scheduling logic

## Description
PRIORITY: LOW -- display/reporting only, not consumed by any scheduling logic. Split 2026-08-30 from bug-1735 at user request: the 'statistics-only' half of that finding -- resource usage fields with no scheduling relevance, purely for operator-facing job accounting/reporting (bjobs -l/bhist-style views), as opposed to bug-1735's memory+CPU-time core, which is a prerequisite for future scheduling decisions. Worker (collect_job_rusages(), xcecd_cgroups.c) already measures and sends 'memory_swap' and 'tasks_current' per job, but the controller has NO field to receive them at all (xce_host_runusage_t only has cpu_time/mem_usage -- no swap or task-count field exists) -- these two are silently dropped entirely, not just misnamed. Separately, xce_job_runusage_t's peak/efficiency fields (peak_cpu_time, peak_cpu_duration, mem_efficiency, avg_cpu_efficiency, peak_cpu_efficiency) have no computation logic anywhere in the codebase (grepped) -- nothing populates them, ever, regardless of bug-1735's fix.

## Environment
_Not recorded (migrated from buglog.json)._

## Reproduction
_Not recorded (migrated from buglog.json)._

## Root cause
See bug-1735's root_cause for the full original investigation (resname-mismatch mechanism, environment-limitation note re: this session's sandbox having no real cgroup-backed worker to live-verify against) -- this entry covers only the subset of that finding split out as lower-priority. Unlike bug-1735's memory/cpu_time (which have existing-but-mismatched fields), memory_swap/tasks_current have NO receiving field in xce_host_runusage_t at all -- the worker's measurement is a complete dead end on the controller side, not a naming mismatch. The peak/efficiency fields (xce_job_runusage_t's own top-level fields) are simply never computed by anything, anywhere -- confirmed via grep, no partial implementation exists to build on.

## Fix
PARTIALLY FIXED (2026-08-30). Of the two gaps this entry covers:

(1) memory_swap/tasks_current -- FIXED. Added mem_swap (double)/tasks_current (int) fields to xce_host_runusage_t (types.h), matching capnp fields (memSwap @3/tasksCurrent @4) appended to the HostRunusage schema (controller.capnp) for WAL field-completeness, parsing in update_host_runusage() (misc.c) for the worker's 'memory_swap'/'tasks_current' resnames, and per-host copy in merge_job_runusage()'s (job.c) existing-host branch (the new fields would otherwise have been silently dropped on WAL replay/catchup for a host already seen).

(2) peak_cpu_time -- FIXED. aggregate_job_runusage() (misc.c) now tracks it as the running MAX of the per-call cpu_time sum across every report a job has ever received (not just the latest), guarding against a later report reducing it (e.g. an out-of-order merge/replay).

STILL NOT FIXED, DELIBERATELY (documented scope decision, not an oversight -- see aggregate_job_runusage()'s own doc comment in misc.c): peak_cpu_duration and the three efficiency fields (mem_efficiency/avg_cpu_efficiency/peak_cpu_efficiency). These need a 'used vs. requested' ratio against a job's resource request (a resreq expression tree, not a plain core/slot count) and/or an unspecified duration semantic -- genuine product/design decisions, not a formula that can be safely guessed. Left at their existing zero value rather than populated with an invented number that could mislead an operator.

Verified: full `meson test --suite controller` clean, Ok:6 Fail:0, 1220/1220 individual controller_unit_test cases pass (zero regression from touching the shared xce_host_runusage_t struct + its capnp schema), plus 2 new regression tests in test_host_runusage.c (7/7 cases pass).

## Verification
_Not recorded (migrated from buglog.json)._

## References
- Related: bug-1735